Patent GB-693965-A (GB)
Title: Improvements in or relating to a process of obtaining crystalline dextrose
Filed: 1949-11-08
Abstract: 693,965. Dextrose. CORN PRODUCTS REFINING CO. Nov. 8, 1949 [Aug. 6, 1949], No. 28576/49. Class 127. A method of obtaining crystalline dextrose from a liquor resulting from the acid conversion of starch comprises the preliminary steps of removing acidity from the liquor and clarifying it, subsequently passing the liquor to ion exchange resins to demineralize and refine it, passing the effluent liquor over a carbon for final decolorization of the liquor and concentrating the liquor before and/or after decolorization and subjecting the concentrated liquor to crystallization ; purging the massecuite of its mother liquor, reconverting the mother liquor, and thereafter subjecting the reconverted mother liquor and freshly converted acidic starch liquor to the preliminary steps and to the subsequent treatment before crystallization, the mother liquor, which is purged from the massecuite, being mixed with the fresh starch and the mixture converted, or the mother liquor being reconverted separately from the conversion of the fresh starch and the reconverted mother liquor and the freshly converted starch liquor being combined at any point in the process prior to crystallization, whereby substantially all the dextrose present in the liquors is recovered in pure crystalline form. The reconverted mother liquor may be added to freshly converted acidic starch liquor and a mixture of liquors subjected to the preliminary and subsequent treatment before crystallization. The reconverted mother liquor may alternatively be subjected after the preliminary steps to the subsequent treatment before crystallization the resulting concentrated reconverted liquor being added to the concentrated liquor and the combined liquor subjected to crystallization. In an Example starch liquor converted at 1 is introduced into a vessel 2 with about 0.5 per cent of bentonite and the material mixed to coagulate impurities such as colloidals. The liquor is then filtered at 3, preferably treated at 4 with colour removing activated vegetable carbon filtered at 5 and cooled to about 145 F. or below and then passed in counter current successively through columns 6, 7, 8, 9, 10, 11 containing alternately anion and cation exchange resins and finally emerging with a pH of 4.0. The demineralized and refined liquor is concentrated in evaporators at 12 to 30 BaumÚ, treated at 13 with a virgin activated carbon to remove residual colour and after filtration at 14 concentrated at 15 to a density of 39 BaumÚ, cooled and introduced into crystallizer 16. The massecuite from the crystallizer is discharged to centrifuge 17 where, after being purged from other liquor, the body of dextrose is washed with water the wash water being returned to the process at 3 and the pure dextrose being discharged from centrifuge 17 and is dried and packed in the conventional manner. The mother liquor discharged from the centrifuge 17 is adjusted to a density of 10.4 BaumÚ, mixed with sulphuric acid and introduced into converter 18 and hydrolized for 30 minutes,'the reconverted liquor being then introduced into 2 along with freshly converted starch hydrolysate liquor and thereafter the combined liquors are de-mineralized and refined, concentrated and crystallized as described. The reconverted liquor may be clarified, demineralized and refined and concentrated in a separate channel and added to freshly converted starch liquor similarly treated and the combined liquors subjected to crystallization. Specification 683,478 is referred to.